There are a number of different mobile radio communication systems commonly in use, and consumers typically chose to subscribe to one that provides service in their location or region. Each system uses a particular, and typically standardized, air interface that specifies radio operation such as signal timing, frequency, modulation, and other aspects of radio operation. Different systems in a given region can each use a different air interface. Although multi-mode communication devices have been made that can access more than one type of air interface, communication devices are more commonly designed to operate using only one air interface. One reason communication devices are typically single mode devices is that a multi-mode device requires more hardware to facilitate multi-mode operation, and consumers generally prefer smaller devices. Advances in circuit integration have somewhat alleviated the size issue. However, another reason multi-mode devices have not gained in popularity is that they typically operate on only one air interface at a time, and the user has to select and switch between air interfaces because operation on more than one air interface at a time can result in the device exceeding regulated specific absorption rate (SAR) levels set by various national and international agencies. As a result, a multi-mode device ends up operating effectively as a single mode device, but one that can be reconfigured to operate on different air interfaces.
Accordingly, there is a need for a means by which a multi-mode communication device can operate on more than one air interface at a time without exceeding regulated SAR levels.
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The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.